In immunology, a state of excessive and potentially damaging immune responsiveness as a result of previous exposure to antigen. If the hypersensitivity is of the immediate type (antibody-mediated), then the response occurs in minutes; in delayed hypersensitivity the response takes much longer (about 24h) and is mediated by primed T-cells. Hypersensitivity responses are not simply divisible into the two types, and it is now more common to subdivide immediate responses into types I, II, and III, the delayed response being of type IV. Type I responses involve antigen reacting with IgE fixed to cells (usually mast cells) and are characterized by histamine release; anaphylactic responses and urticaria are of this type. In type II responses circulating antibody reacts with cell surface or cell-bound antigen, and if complement fixation occurs, cytolysis may follow. In type III reactions immune complexes are formed in solution and lead to damage (serum sickness, glomerulonephritis, Arthus reaction). Delayed-type responses of Type IV involve primed lymphocytes reacting with antigen and lead to formation of a lymphocyte-macrophage granuloma without involvement of circulating antibody.
Excessive sensitivity of plant tissues to certain pathogens. Affected cells are killed quickly, blocking the advance of obligate parasites. Also an immune reaction, usually harmful to the animal, caused either by antigen-antibody reactions or cellular-immune processes.
- pathological sensitivity
- extreme sensitivity
Hypersensitivity (also called hypersensitivity reaction or intolerance) refers to undesirable reactions produced by the normal immune system, including allergies and autoimmunity. These reactions may be damaging, uncomfortable, or occasionally fatal. Hypersensitivity reactions require a pre-sensitized (immune) state of the host. They are classifie...Found on http://en.wikipedia.org/wiki/Hypersensitivity
(hi;per-sen;su1-tiv;u1-te) Another name for allergy; abnormal immune response that may be immediate (due to antibodies of the IgE class) or delayed (due to cell-mediated immunity).Found on http://www.mhhe.com/biosci/abio/glossary.mhtml
(hi″pәr-sen″sĭ-tiv´ĭ-te) a state of altered reactivity in which the body reacts with an exaggerated immune response to a foreign agent; anaphylaxis and allergy are two types. The hypersensitivity states and resulting hypersensitivity reactions are usually subclassified by the Gell and Coombs classi...Found on http://www.encyclo.co.uk/local/21001
- pathological sensitivity 2. [n] - extreme sensitivityFound on http://www.webdictionary.co.uk/definition.php?query=hypersensitivity
<immunology> A state of altered reactivity in which the body reacts with an exaggerated immune response to a foreign substance. Hypersensitivity reactions are classified as immediate or delayed, types I and IV, respectively, in the Gell and Coombs classification of immune responses. ... (18 Nov 1997) ... Found on http://www.encyclo.co.uk/local/20973
extreme sensitivityFound on http://wordnetweb.princeton.edu/perl/webwn?s=hypersensitivity
a sharp, sudden painful reaction in teeth when exposed to hot, cold, chemical, mechanical or osmotic (sweet or salt) stimuli.Found on http://www.1stdentalcare.com/glossary.shtml
a sharp, sudden painful reaction in teeth when exposed to hot, cold, chemical, mechanical or osmotic (sweet or salt) stimuli.
Found on http://www.cosmeticdentistryguide.co.uk/glossary.html
a state of altered reactivity in which the body reacts with an exaggerated immune response to a foreign substance. Hypersensitivity reactions are classified as immediate or delayed, types I and IV, respectively, in the Gell and Coombs classification (q.v.) of immune responses.Found on http://users.ugent.be/~rvdstich/eugloss/DIC/dictio41.html
acquired bodily state in which the reaction to a stimulus (e.g., a substance causing allergy or a physical agent such as light) is unusually prompt ...Found on http://www.britannica.com/eb/a-z/h/91
An exaggerated response by the immune system to a drug or other substance.Found on http://www.cancer.gov/dictionary?expand=H
an excessive response of the body's immune system to a foreign protein Found on http://www.medichecks.com/glossary.cfm?ltr=H
Excessive immune response that leads to undesirable consequences (e.g., tissue or organ damage).Found on http://www.roitt.com/glossary.asp
Excessive sensitivity to certain external factors (over-reaction by immune system causing allergic symptoms).
Found on http://www.encyclo.co.uk/local/20667
hypersensitivity Abnormally acute sensitivity.Found on http://www.wordinfo.info/words/index/info/view_unit/1018/11
hypersensitivity, heightened response in a body tissue to an antigen or foreign substance. The body normally responds to an antigen by producing specific antibodies against it. The antibodies impart immunity for any later exposure to that antigen. When exposure takes place under certain physiologica...Found on http://www.infoplease.com/ce6/sci/A0824767.html
It is an exaggerated reaction of the body’s defence system to basically harmless substances which may have been inhaled, eaten, drunk, injected or just been in contact with the skin.Found on http://www.vidyagyaan.com/general-knowledge/science/list-of-glossary-of-zoo
See allergy.Found on http://www.chemicalglossary.net/definition/884-Hypersensitivity
State in which an individual reacts with allergic effects following exposure to a certain substance (Found on http://sis.nlm.nih.gov/enviro/iupacglossary/glossaryh.html
State of reactivity to antigen that is greater than normal for the antigenic challenge; hypersensitivity is the same as allergy and denotes a deleterious outcome rather than a protective one.
Found on http://www.encyclo.co.uk/local/21016
The condition of being excessively sensitive (overreacting) to the effects of an action or a substance, e.g., the immune system can become hypersensitive to foreign particles such as dust or pollen, which can lead to an allergic reaction. The nervous system may also become hypersensitive to stimulation.
Found on http://www.encyclo.co.uk/local/20560
The expression of extreme reactivity by a plant in response to a potential parasite or pathogen, the plant's response commonly serving to limit or prevent parasitization/disease. Found on http://ppathw3.cals.cornell.edu/glossary/Defs_H.htm
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